1. Field of The Invention
The present invention relates generally to the field of agricultural equipment, and particularly to pivot monitors and controllers for center pivots.
2. Description of the Related Art
Center pivots are commonly used to irrigate large ureas of land that are typically a half mile on each side or quarter section. The center pivot includes a base that is attached to the ground and number of segments attached together that are supported on wheels for allowing them to rotate around the base. With the advance in technology, remote telemetry units to monitor pivots and control their functionality are becoming more common. A remote telemetry unit on a center pivot is commonly referred to as a pivot monitor.
Pivot monitors are typically installed in the main panel or at the end tower of a center pivot. Installing a pivot monitor at the end tower allows the unit to include a GPS receiver to determine the hearing of a pivot in a field. A unit installed in a main panel may rely on dead reckoning to determine the pivot bearing, but much less accurately than a GPS unit. The bearing of the pivot may be used to apply watering prescriptions or to control end gun zones.
Watering prescriptions for a center pivot are based on factors such as soil type, terrain, and historical yield data. The watering prescription alters a set application rate to be higher or lower depending on if a region covered by the field needs more or less water. Applying a watering prescription uses the speed control feature of a pivot monitor.
Certain irrigated fields have center pivots that cannot make a complete circle. These types of center pivots are called wiper pivots due to the resemblance in path of a windshield wiper. When a wiper center pivot approaches the edge of the field it is desirable in some circumstances to approach the edge of the field at one speed and leave at a different speed. Typically, an operator would want to approach the field edge at a higher rate and leave at a slower rate to prevent the pivot tire tracks from becoming unnecessarily deep.
Current center pivot controllers accomplish the differing approach and exit speeds by using two speed tables. One table is used to control the speed in the forward direction and the other is used to control the speed in the reverse direction. The limitation of this method is that it requires additional user setup, is prone to entry error, and consumes twice the memory in the pivot controller. Speed tables for center pivots may include several hundred rows of data, which is significant for the types of microcontrollers used in pivot monitors. Therefore, there is a need for a pivot monitor that can easily adjust the speed of a wiper pivot in an easier and more memory efficient manner.
In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced.